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JavaScript JavaScript Loops, Arrays and Objects Tracking Multiple Items with Arrays Using For Loops with Arrays

Natalia Karolinskaya
Natalia Karolinskaya
9,367 Points
Posted by Natalia Karolinskaya
Natalia Karolinskaya
9,367 Points

I don't understand two things in this exaple

https://w.trhou.se/rxigpql9yw

  1. listHTML += '<li>' + list[i] + '</li>';

Initial value of i is 0, so ho come the list starts with number 1?

  1. I don't see where in the function printList we instruct it to print the playList? I mean we say print playList in the end, but that is note the function code anymore.

Thanks for your help!

2 Answers

Chyno Deluxe
Chyno Deluxe
16,936 Points
Chyno Deluxe
Chyno Deluxe
16,936 Points

An arrays index begins at 0 so that is why the inital value of i = 0. 

var playList = [
  'I Did It My Way', // playList[0]
  'Respect', // playList[1]
  'Imagine', // playList[2]
  'Born to Run', // playList[3]
  'Louie Louie', // playList[4]
  'Maybellene' // playList[5]
];

So the printList function cycles through the playlist array and prints them out.

function printList( list ) { // list = playList[]

  var listHTML = '<ol>';

//This for loop prints out each item in the playList array
  for (var i = 0; i < list.length; i += 1) {
    listHTML += '<li>' + list[i] + '</li>';
  }
  listHTML += '</ol>';
  print(listHTML);
}
printList(playList); // playList is called as an argument in the printList function
john larson
john larson
16,594 Points
john larson
john larson
16,594 Points

alright, I have the same questions as noted above...and I will raise you this one. WHY does list = playList. That is not mentioned thus far that I can see. If it is an understood shortcut of some sort, I would have been less confused if that were mentioned in the lesson.

Chyno Deluxe
Chyno Deluxe
16,936 Points

list = playList because you call the printList() function with playList as the argument.

printList(playList);

The parameter list could be called anything and It would still equal to playList[]. View Below

function printList( k ) { // k = playList[]

  var listHTML = '<ol>';

//This for loop prints out each item in the playList array
  for (var i = 0; i < k.length; i += 1) {
    listHTML += '<li>' + k[i] + '</li>';
  }
  listHTML += '</ol>';
  print(listHTML);
}
printList(playList); // playList is called as an argument in the printList function

I hope this helps. Feel free to ask me another other questions you may have.